中文版
 

Prof. Xiangang Wan: Towards ideal topological materials: Comprehensive database searches using symmetry indicators (2019/03/18)

( 2019-03-12 )

Title

Towards ideal topological materials: Comprehensive database searches using symmetry indicators

Speaker

Prof. Xiangang Wan

School of Physics,

Nanjing University           

Time

3:00pm, March 18, 2019

Place

Exhibition Hall at the HFNL building

Brief Bio of the Speaker

万贤纲,南京大学物理学院教授,1990年至2000年在南京大学学习,获得学士、硕士、博士学位。2001起在南京大学历任讲师,副教授,2010年任教授。主要学术成绩为:提出了新型拓扑量子态—Weyl 半金属,引发了国际上Weyl 半金属的研究热潮;发展了一套计算磁性相互作用的方法并确定多个复杂体系的基态磁构型;基于原子绝缘体基组发展了高效判断拓扑性能的理论方法,并用其对无机材料数据库里面所有非磁材料的拓扑特性进行了分类。获得2014年度香港大学Daniel Tsui Fellowship2015年获得国家杰出青年科学基金;2016年被评为教育部长江学者特聘教授。

Abstract

Although the richness of spatial symmetries has led to a rapidly expanding inventory of possible topological crystalline (TC) phases of electrons, physical realizations have been slow to materialize due to the practical difficulty to ascertaining band topology in realistic calculations. Here, we integrate the recently established theory of symmetry indicators of band topology into first-principle band-structure calculations and apply it to all non-magnetic compounds in the 230 space groups. An exhaustive database search reveals thousands of TM candidates. Of these, we highlight the excellent TMs, the 258 topological insulators and 165 topological crystalline insulators which have either noticeable full band gap or a considerable direct gap together with small trivial Fermi pockets. We also give a list of 489 topological semimetals with the band crossing points located near the Fermi level. All predictions obtained through standard generalized gradient approximation (GGA) calculations were cross-checked with the modified Becke-Johnson (MBJ) potential calculations, appropriate for narrow gap materials. With the electronic and optical behavior around the Fermi level dominated by the topologically non-trivial bands, these newly found TMs candidates open wide possibilities for realizing the promise of TMs in next-generation electronic devices.

[1] Efficient Topological Materials Discovery Using Symmetry Indicators, Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan*, Nature Physics (2019) DOI:10.1038/s41567-019-0418-7

[2] Comprehensive search for topological materials using symmetry indicators, Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan*, Nature 566, 486 (2019).

[3] Efficient Topological Materials Discovery Using Symmetry Indicators, Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan*, Science Advances 5, eaau8725 (2019).


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